The present invention relates to a surgical device for creating precise, small skin incisions for the introduction of a percutaneous conduit. In particular, the invention relates to such a device which is designed for creating a small skin incision of controlled geometry about a puncture created by a guidewire or needle for the purpose of introducing a catheter or other percutaneous conduit. The invention also relates to an antimicrobial cuff for the conduit, to a device for positioning the cuff via the precision incision, and to methods of using the cutter, cuff and introducer.
A percutaneous device or conduit is an implement which passes through the skin, allowing the linkage of an intracorporeal organ or cavity with extracorporeal equipment. There exists a wide variety of clinical applications for percutaneous devices. For example, in the facilitation of fluid transport, percutaneous conduits, or catheters, are used to access blood for dialysis, pressure monitoring, or laboratory diagnosis, to deliver drugs or nutritional solutions, and to drain wound exudate.
In the clinical placement of catheters, it is often necessary to create a small skin incision across the puncture initially created by a needle, to allow the introduction of the larger diameter catheter. The conventional procedure for performing this catheter placement is shown schematically in FIGS. 1 through 3. As shown in FIG. 1, initially the skin 13 is punctured with a guidewire or needle 11, at a desired location 12, and the wire is inserted through the epidermis 14, dermis 15 and subcutaneous tissue 16 to provide intracorporeal access to the deeper tissues.
Then, referring to FIG. 2, two incisions 18 and 19 are made at opposite sides of the guidewire 11. Typically, the two incisions are made with a No. 11 scalpel blade (designated by reference numeral 21) or an equivalent device by placing the non-cutting edge against the guidewire 11 and cutting outwardly from the wire, then repeating the operation in the opposite direction. Finally, as shown in FIG. 3, a catheter 22 is inserted along the guidewire 11 through the skin 13 into the deeper tissues.
The skin incision step is of particular relevance to our discussion, and to the present invention, for it is difficult to make a cut of the desired width and depth necessary for introduction of the catheter 22 without forming a cut either greater or smaller than desired. Furthermore, care must be taken not to sever the guidewire when making the skin incision, since the resulting internal piece of wire might then travel harmfully within the vascular system.
U.S. Pat. No. 4,438,770, issued Mar. 27, 1984 to Unger et al discloses a spring-biased skin incising device which is designed to provide an incision of controlled length and depth. To make an incision, the cutter, which is mounted within a support base, is cocked and the base is positioned on the patient's skin at the site of the incision. The cutter is then released and the spring automatically displaces the cutter along a guide slot to make a cut of controlled depth and length. The device provides only a single cut and, thus, would require two cutting operations to make a catheter incision, similar to the situation using a conventional scalpel (see FIG. 2). Furthermore, the cutter is surrounded by the base so that, apparently, it would be impossible to make a cut adjacent the guidewire 11.